管道高级操作

需求：将爬取到的数据值分别存储到本地磁盘、redis数据库、mysql数据。

　　1.需要在管道文件中编写对应平台的管道类

　　2.在配置文件中对自定义的管道类进行生效操作（在pipelines里面定义的类，加进settings.py里面 pipelines对应的里面，后面数字大小无所谓）

 

pipelines.py

# -*- coding: utf-8 -*-

# Define your item pipelines here
#
# Don't forget to add your pipeline to the ITEM_PIPELINES setting
# See: https://doc.scrapy.org/en/latest/topics/item-pipeline.html
import pymysql


class QiubaiPipeline(object):
    conn = None
    # 该方法只会在爬虫开始运行的时候调用一次
    cursor = None

    def open_spider(self, spider):
        print("开始爬虫")
        # self.fp = open("./data_record.txt", "w", encoding="utf-8")
        self.conn = pymysql.Connect(host="127.0.0.1", port=3306, user="root", password="1228", db="qiubai")
    # 该方法就可以接受爬虫文件中提交过来的item对象，并且对item对象中存储的页面数据进行持久化存储
    # 参数item就是接收到的item对象
    # 每当爬虫文件向管道提交一次item,则该方法就会被执行一次

    def process_item(self, item, spider):
        # 取出item中的对象存储数据
        author = item["author"]
        content = item["content"]
        # 持久化mysql存储

        sql = "insert into data values ('%s', '%s')" % (author, content)
        print(sql)
        # self.fp.write(author + ":" + content + "


")
        self.cursor = self.conn.cursor()
        try:
            self.cursor.execute(sql)
            self.conn.commit()
        except Exception as e:
            print(e)
            self.conn.rollback()

        return item

    # 该方法只会在爬虫结束时调用一次

    def close_spider(self, spider):
        print("爬虫结束")
        # self.fp.close()
        self.conn.close()


class QiubaiByFiles(object):
    def process_item(self, item, spider):
        print("数据已写入磁盘文件中")
        return item


class QiubaiByredis(object):
    def process_item(self, item, spider):
        print("数据写入redis中")
        return item